LiquidDraupner static test - 2006-10-28

Static test of LiquidDraupner liquid fuel N2O/IPA rocket motor

LD_static_test_2006_10_28

LiquidDraupner motor features

Propellant Isopropyl alcohol (IPA) and nitrous oxide (N2O).
Tank structure Ø110mm extruded aluminium tube with machined aluminium end caps.
Tank layout Both propellants in the same tank, separated by floating bulkhead. IPA at the top.
N2O pressurization N2O vapour pressure.
IPA pressurization N2O vapour pressure through floating bulkhead.
IPA feed pipe Coaxial through tank tube.
Chamber structure Extruded aluminium tube.
Chamber liner Replaceable ablative phenolic liner (slip fit in chamber tube).
Nozzle Stainless steel.
Injector Machined aluminium with 4 IPA/N2O impinging injector hole sets.
Main valves Mechanically linked ball valves, mounted on tank end cap.
Ignition Cylindrical solid propellant grain inside combustion chamber.

In this test, the main valves where released by a cord looped over the nozzle exit. The solid propellant grain was ignited first and then the hot gasses burned through the cord. The main valves then opened by a spring actuator. This system resulted in very fast propellant flow build up and some deformation of the chamber tube due to the resulting pressure spike. However the chamber tube was not breached and the motor completed the burn without further damage.

This article was first published 2010-12-05.